1. Field of the Invention.
The invention relate to a rapid deflation system for a pneumatic seat cushion useful in aircraft.
2. Description of the Prior Art
The seats of many tactical aircraft are uncomfortable to the pilots or crewmembers even for short missions. Because of the firmness of the cushions used in the present seating systems, there is a considerable, sometimes partially debilitating amount of discomfort experienced by those persons required to use the seats. The discomfort grows with time and with the manner in which the seat is used. For example, if the seat is in a maneuvering aircraft, the user feels higher pressures on the body/seat contact points during so called "positive `g`" maneuvers that can result in greater discomfort. A cushion that is less firm would decrease the discomfort, but at the greater risk of serious injury during ejection.
For an ejection-seat-equipped aircraft, the risk of sitting on a soft cushion is enormous. During an ejection sequence while sitting on the very firm standard issue seat cushion, the crewmember and seat accelerate out of the aircraft as one. That acceleration is carefully tailored to generate the maximum force that a pilot can reasonably tolerate. If that crewmember were to add a soft cushion between himself and the seat, the stage is set for disaster. Should an ejection sequence be initiated while on the soft cushion, the crewmember would at first remain stationary while the seat accelerated and the cushion compressed. Eventually the now fast moving seat would come crashing into the crewmember's posterior with great force likely causing serious spinal injury. Present seating systems avoid that impact by making the cushions so thin and firm that the occupant accelerates practically as one with the seat.